Press   Bulletin  Series  Issued  Twice  Quarterly 

STATE  OF  ILLINOIS 
DEPARTMENT  OF  REGISTRATION  AND  EDUCATION  .    -..■'-""     " 


A.  M.  SHELTON.  Director 


Ul  V  1J1V1\     V_T      1  I  IE  (TV    !' 

STATE  GEOLOGICAL  SURVEY^  1\   ,        J  r  -    $& 

M.  M.  LEIGHTON.  Cfee/;    Urbana 

No.    6  ILLINOIS   PETROLEUM  December  4,  1926 

THE  SORENTO  DOME 

By  Alfred  H.  Bell 

Introduction 

All  but  one  of  the  known  oil  and  gas  fields  of  southwestern  and  south- 
central  Illinois  lie  within  a  rectangle  70  miles  long  and  18  miles  wide,  extend- 
ing in  a  northwesterly  direction  from  Centralia  to  Carlinville.  (See  fig.  1.) 
Practically  without  exception  they  are  situated  upon,  or  are  closely  related 
to,  well-defined  anticlinal  structures.  In  order  to  reduce  as  much  as  possible 
the  risk  involved  in  prospecting  for  oil  in  this  territory,  drilling  should  be 
preceded  by  (1)  a  search  for  favorable  structures  hitherto  unknown  and 
i  '.'  |  a  reconsideration  of  the  data  relating  to  known  favorable  structures. 
This  paper  gives  briefly  the  results  of  a  restudy  of  the  Sorento  dome  in  parts 
of  Madison,  Montgomery  and  Bond  counties. 

In  a  former  publication1  the  dome  was  represented  by  contours  indicat- 
ing the  elevation  above  sea  level  of  Elerrin  (No.  6)  coal  and  having  an 
interval  of  50  feet ;  it  is  here  represented  in  greater  detail  by  contours  on 
the  same  key  bed  having  a  10-foot  interval.  A  restudy  of  the  data  has 
shown  that  what  has  been  known  as  the  "Sorento  dome"  really  consists  of 
two  parts.  In  this  report  these  will  be  referred  to  as  the  New  Douglas  dome, 
which  centers  about  a  well  in  NE.  34  sec-  10>  T.  6  N.,  R.  .5  W.,  and  the 
Panama  anticline  which  lies  about  1  mile  west-southwest  of  Panama. 

Stratigraphy 

An  outline  of  the  stratigraphic  section  for  the  Sorento  dome  area  is 
given  in  table  1 .  The  data  have  been  taken  partly  from  the  column  given 
by  Wallace  Lee2  and  have  been  partly  compiled  from  a  study  of  well  logs. 
It  will  be  noted  that  there  is  considerable  disagreement  between  the  pre- 
Mississippian  section  as  interpreted  in  this  report  and  the  section  given 
by  Lee. 


1  Blatchley,    R.    S.,    Oil   and   gas   in    Bond,    Macoupin,    and    Montgomery    counties,    Illi- 
nois:    Illinois  State  Oeol.  Survey  Bull.  28,  PI.   II,  1914. 

2  Lee.    Wallace,    U.    S.    Oeol.    Survey    Geol.    Atlas,    Gillespie-Mount    Olive    folio    (No. 
220),  p.  3,  1926. 


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4  ILLINOIS    PETROLEUM 

The  log  of  the  Mark  Flitz  well,  in  sec.  24,  T.  8  N.,  R.  5  W.,3  was  com- 
pared with  the  logs  of  two  other  deep  wells — the  Varner  well,  sec.  3,  T.  8  N., 
R.  5  W.,  and  the  Clint  Bliss  well,  sec.  9,  T.  8  N.,  R.  3  W.  The  comparison 
indicates  that  the  strata  which  Lee  correlated  as  Maquoketa  in  reality  in- 
clude the  Sweetland  Creek  shale  and  a  portion  of  the  Kinderhook.  The  St. 
Peter  sandstone  was  not  reached  in  the  Mark  Flitz  well  which  finished  in 
the  Kimmswick-Plattin  limestone,  315  feet  below  its  top. 

In  drilling  wildcat  wells,  the  efficiency  of  drilling  is  limited  by  a  lack 
of  knowledge  of  the  depth  and  exact  character  of  the  beds  to  be  penetrated. 
Lateral  variations  in  thickness  and  lithologic  character  of  the  strata  as  well 
as  the  dip  of  the  strata  are  the  factors  to  which  this  lack  of  knowledge  is 
due.  In  order  to  minimize  the  difficulty,  an  estimated  depth  to  the  top  of 
each  formation  which  would  be  encountered  in  a  well  drilled  near  the  top 
of  the  New  Douglas  dome  is  included  in  the  stratigraphic  table.  The  esti- 
mated depths  are  based  on  the  logs  of  several  wells,  of  which  the  deeper 
ones  are  located  farther  from  the  top  of  the  structure  than  are  the  shallower 
ones  ;  consequently  they  are  likely  to  be  more  nearly  correct  for  the  upper 
than  for  the  lower  formations.  Thus  the  deepest  well  in  the  area,  which 
reached  approximately  the  base  of  the  Osage,  is  located  on  the  Smith  farm, 
sec.  15,  T.  ?  N.,  R.  5  W.,4  1  miles  north  of  the  top  of  the  structure.  The 
nearest  well  that  reached  the  Kimmswick-Plattin  ("Trenton")  is  9  miles 
north;  the  nearest  well  that  reached  the  St.  Peter  sandstone  is  16  miles 
northeast. 

Structure 

Structure  is  represented  on  the  accompanying  contour  map  (fig.  2)  by 
contours  which  give  the  elevation  above  sea  level  of  Herrin  (No.  6)  coal  or, 
in  case  this  coal  is  absent,  of  its  probable  stratigraphic  horizon  as  inferred 
from  the  correlation  of  other  beds.  Table  2  gives  the  data  on  which  the 
contours  are  based.  On  account  of  the  superior  information  given  by  core 
drilling,  the  logs  obtained  can  in  most  cases  be  readily  correlated  with  each 
other  and  it  is  believed  that  considerable  reliance  can  be  placed  on  structure 
maps  which  are  based  on  such  logs  in  areas  where  the  wells  are  relatively 
closely  spaced.  The  logs  of  the  churn  drill  wells  in  this  area,  on  the  other 
hand,  are  not  easily  correlated  with  each  other  or  with  the  logs  of  diamond 
drill  coal  test  wells.  They  have,  therefore,  not  been  considered  in  the  con- 
struction of  the  accompanying  map  (fig.  2).  The  elevations  of  wells  in 
T.  6  N.  were  determined  by  stadia  survey  by  the  writer's  party  with  the 
exception  of  the  wells  in  sees.  23  and  24,  T.  6  N.,  R.  5  W.,  and  sec.  20, 
T.  6  N.,  R.  4  W.,  for  which  the  elevations  were  determined  by  aneroid. 
The  elevations  of  the  wells  in  T.  7  N.  and  in  sec.  2,  T.  6  N.,  R.  4  W..  were 


Lee,  Wallace,  op.  cit.,  p.  3. 

For  the  log  of  this  well,  see  Lee,  Wallace,  op.  cit.,  p. 


SOEENTO    DOME  5 

taken   from  various  sources  and,  with  very   few  exceptions,  they  had  been 
obtained  originally  by  stadia  survey. 

The  map  shows  the  two  rather  distinct  parts  of  the  Sorento  dome 
referred  to  in  the  introduction  to  this  report.  The  top  of  the  New  Douglas 
dome  lies  approximately  in  sec.  10,  T.  6  N.,  R.  5  W. ;  the  highest  part  of 
the  Panama  anticline  lies  west-southwest  of  Panama  (sec.  22,  T.  ~i  N., 
R.  4  W.).  It  is  probable  that  a  continuous  anticlinal  axis  connects  these 
two  structural  highs. 

The  determination  of  the  entire  upper  part  of  the  structure  of  the  New 
Douglas  dome  depends  on  the  interpretation  of  the  log  of  one  well  (Map 
No.  25,  Ameling  No.  4.  sec.  10,  T.  (J  N.,  R.  5  W.)  and  this  log  shows  the 
absence  of  Herrin  (No.  6)  coal,  the  bed  on  which  the  contours  of  figure  2 
are  drawn.  In  order  to  determine  the  stratigraphic  horizon  of  this  key  bed, 
a  cross-section  of  two  wells  (  Nos.  25  and  19)  and  one  mine  shaft  (No.  27) 
was  drawn  (fig.  3).  The  evident  correlation  of  the  other  beds,  as  shown  in 
the  cross-section,  places  the  horizon  of  the  top  of  the  coal  very  definitely  as 
indicated  and  there  seems  to  be  little  room  for  doubt  as  to  the  accuracy  of 
this  interpretation. 

Figure  3  shows  a  dip  of  more  than  a  hundred  feet  from  well  No.  25  to 
the  mine  and  the  dips  from  the  center  of  the  structure  in  all  directions  ex- 
cept to  the  northwest  ( as  shown  in  figure  2 )  appear  to  be  fairly  well 
authenticated. 

Development 

Six  churn  drill  wells  have  been  drilled  in  the  area,  of  which  all  but  two 
were  unfavorably  located  with  respect  to  structure.  Each  of  the  other  two 
was  within  a  mile  of  the  anticlinal  axis  (sec.  20,  T.  7  N.,  R.  4  W.,  and  sec. 
35,  T.  ~,  N..  R.  5  W.).  Only  a  very  incomplete  record  of  the  latter  is  avail- 
able. It  gives  Herrin  (No.  6)  coal  from  325  to  332  feet  and  sand  from  610 
to  700  feet ;  the  sand  is  probably  Pottsville.  The  first  well  has  the  following 
sand  record : 

Feet 

Sandy    shale 325  to  370 

Sand    660  to  690   ( probably  Pottsvillo ) 

Sandy    shale 690  to  710 

Sandy    shale 736  to  765 

The  St.  Louis  limestone  ("Mississippi  lime")   was  topped  at  765  feet.     The 
casing  record  was  as  follows : 

10-inch 20   feet 

S^-inch 402   feet 

6%-inch 695  feet 

A  well  in  sec.  15,  T.  7  N.,  R.  5  \\\,  had  a  showing  of  gas  in  a  sand  at 
586  feet  and  a  showing  of  oil  lower  in  the  same  sand  from  5S  I  to  618  feet. 


ILLIXOIS    PETROLEUM 


Table  2. — Well  data  from  Sorento  Dome  area 

"Map 

Company 

Well 
No. 

Surface 

Elevation 

Feet 

No.  6 

coal 

No. 

Depth 

Elevation 

Feet 

Feet 

1 

Whitebreast  Fuel 

I 

611 

458 

153 

2 

Whitebreast  Fuel 

M 

519 

360 

159 

3 

591 

377 

214 

4 

Whitebreast  Fuel 

E 

527 

295 

232 

5 

Whitebreast  Fuel 

F 

525 

353 

172 

6 

Shoal  Creek  Coal 

538 

374 

164 

7 

Whitebreast  Fuel 

1 

563 

446 

117 

8 

Whitebreast  Fuel 

L 

609 

459 

150 

9 

Lumaghi  Coal 

10 

593 

387 

206 

10 

A.  W.  Crawford 

20 

522 

294 

228 

11 

Sorento  Coal 

585 

384 

201 

12 

Lumaghi  Coal 

7 

584 

400 

184 

13 

Lumaghi  Coal 

26 

595 

415 

180 

14 

650 

390 

260 

15 

640 

395 

245 

16 

Lumaghi  Coal 

1 

600 

364 

236 

17 

Lumaghi  Coal 

5 

582 

373 

209 

IS 

Lumaghi  Coal 

4 

589 

373 

216 

19 

Sorento  Options 

22 

589 

351 

238 

20 

Lumaghi  Coal 

590 

340 

250 

21 

Wilmington  Star  Coal 

585 

342 

243 

22 

H.  R.  Ameling 

6 

592 

357 

235 

23 

H.  R.  Ameling 

9 

591 

234 

257 

24 

H.  R.  Ameling 

15 

613 

356 

257 

25 

H.  R.  Ameling 

4 

580 

285 

295 

26 

H.  R.  Ameling 

1 

577 

374 

203 

27 

Big  Mound  Coal 

605 

415 

190 

2S 

H.  R.  Ameling 

16 

609 

372 

237 

29 

New  Staunton  Coal 

10 

609 

370 

239 

30 

H.  R.  Ameling 

7 

572 

347 

225 

31 

New  Staunton  Coal 

13 

566 

332 

234 

32 

New  Staunton  Coal 

11 

600 

396 

204 

33 

H.  R.  Ameling 

20 

596 

400 

196 

34 

H.  R.  Ameling 

8 

591 

397 

194 

35 

Schallenberg 

614 

437 

177 

36 

H.  R.  Ameling 

3 

565 

370 

195 

37 

Whitebreast  Fuel 

H 

511 

362 

149 

38 

Duncan 

3 

577 

441 

136 

39 

Sullivan   Machinery 

1 

576 

444 

132 

40 

Shoal  Creek  Coal 

2 

574 

443 

131 

41 

Consolidated  Coal 

2 

506 

363 

143 

42 

Consolidated  Coal 

1 

528 

378 

150 

See  figure  2  for  locations. 


SOKENTO    HOME 


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ILLINOIS    PETROLEUM 


Elevation 
in  feet  .  _ 
600,    19 


27 


500 


400 


ss 


300 


200 


100 


100 J 


53=FS 


25 


Herrin 
(ko.G)coal 


\ 


\ 


\ 


\ 
\ 

\ 

Herrin   _v 
(No. 6)  coal 


Shale,  surface  material 


EEE^  Sandy  shale 
\  ■  ■  -.|  Sandstone 


•fr-M  Limestone 


r^tttl  Sandy  limestone 
.^  Coai 


^=^|   Bituminous  shale 
\xxx  xl   Fire  clay 


Salt 
water 


X  X  X   X 


33 


3  miles 


Fig.  3.    Cross-section  through  New  Douglas  dome.     See  fig.  2  for  locations  of 
wells  and  mine  shaft.     (By  A.  H.  Bell,  Illinois  State  Geological  Survey.) 


SOKENTO    DOME  » 

This  sand  probably  belongs  in  tbe  Pottsville  and  may  be  contemporaneous 
with  the  producing  sand  of  the  Staunton  gas  field. 

Recom  mendations 

The  most  important  oil  production  in  southwestern  Illinois  is  from 
sands  of  Chester  age,  and  the  probability  of  the  presence  of  Chester  sands 
over  the  New  Douglas  dome  is  a  favorable  feature  from  the  point  of  view 
of  the  oil  prospector. 

A  study  of  the  logs  shows  that  Chester  rocks  are  present  in  all  the  wells 
shown  on  the  map  that  have  been  drilled  to  a  sufficient  depth  and  it  is  there- 
fore highly  probable  that  the  Chester  is  present  on  top  of  the  New  Douglas 
dome.  The  following  table  lists  these  wells  with  the  thickness  of  Chester 
found  in  each  : 


Taisle  3. — Wells  in  Sorento  Dome  area  penetrating  the  Chester 


Location 

Thickness  of  Chester 

Section 

Township  N. 

Range  W. 

Feet 

15 

7 

5 

80 

24 

7 

5 

80 

20 

7 

4 

80 

24 

6 

5 

125 

15 

6 

4 

record  incomplete 

It  should  be  added,  however,  that  from  general  studies  of  the  surround- 
ing region,  tbe  Chester  is  known  to  thin  out  to  the  west  and  to  thicken  to 
the  east.  The  Chester  is  definitely  absent  in  the  Staunton  gas  field,  so  that 
tbe  western  boundary  of  the  area  in  which  Chester  rocks  are  present  lies 
somewhere  between  the  westernmost  wells  listed  above,  and  the  Staunton 
dome  area — its  precise  location  is  not  known.  Although  it  is  not  absolutely 
certain,  yet  it  is  very  probable  that  Chester  rocks  occur  on  top  of  the  New 
Douglas  dome. 

Besides  the  Chester  there  are  several  other  possible  producing  horizons. 
(See  table  I,  which  lists  the  producing  horizons  in  other  oil  and  gas  fields 
of  central  and  western  Illinois.5 )  Of  these  perhaps  the  most  important  is 
the  Pottsville,  since  to  it  belong  the  gas  sands  of  the  Staunton  and  other 
fields  to  the  north. 

Xo  production  from  rocks  older  than  the  Chester  has  been  obtained 
within  a  radius  of  50  miles.  A  showing  of  oil,  variously  reported  from  10 
to  75  barrels,  was  obtained  in  Brown   Xo.   1.  sec.  9,  T.  .")  N.,  R.    1   W.,  six 

e  figure  1  for  the  Locations  of  most  of  these  fields. 


10 


ILLINOIS    l'KTROLKVM 


miles  south  of  Sorento.  This  oil  was  from  a  sand  of  Devonian  or  Silurian 
age  at  a  depth  of  2000  feet.  The  well  did  not  make  a  commercial  producer 
and  a  number  of  dry  holes  were  drilled  in  the  vicinity. 

It  seems  probable  that  once  the  top  of  the  St.  Louis  limestone  is  reached 
the  most  likely  oil-bearing  strata  have  been  penetrated.  The  advisability  of 
deeper  drilling  is  open  to  question.  If  it  is  desired  to  test  the  structure  very 
thoroughly,  drilling  might  be  continued  to  the  top  of  the  Kimmswick-Plattin 


Table  4. — Producing  horizons  in  central  and  western  Illinois  oil  and  gas  fields 


Depth 
Feet 


285 


610 


690 


1810 


2510 


Horizons 


1.    Pennsylvanian   sands   below   Her- 
rin  (No.  6)  coal 


2.    Chester 


Remarks 


Produce  oil  at  Junction  City  and 
Wamac;  oil  and  gas  at  Carlin- 
ville;  gas  at  Staunton. 


Oil  at  Progtown,  Carlyle,  Sandoval 
and  C  e  n  t  r  a  1  i  a ;  gas  in  Bond 
County,  (1)  A  y  e  r  s,  and  (2) 
Lindly. 


3.    Ste.    Genevieve     (upper    part    of  Oil  in  Lawrence  County. 
"Mississippi  lime");   correlated 
with  "McClosky  sand" 


4.    Devonian  or  Silurian 


5.    Silurian:      "Niagara    lime" 
Hoing  sand. 


and 


6.  Ordovician:  Kimmswick-Plattin 
limestone  ("Trenton  lime- 
stone") 


Showings  of  oil  in  wells  in  Old 
Ripley  Township  (south  of  Ayers 
anticline). 


Gas  in  Pike  County  (Pittsfleld- 
Hadley  anticline),  and  oil  at 
Colmar. 


Oil  at  Waterloo. 


("Trenton").    The  possibility  of  oil  in  commercial  quantities  at  still  greater 
depth  is  decidedly  remote. 

On  the  whole  it  seems  a  better  procedure  to  drill  only  into  the  St.  Louis 
("Mississippi  lime")  and  if  the  first  test  to  this  depth  is  unsuccessful  to  drill 
the  structure  in  another  place  in  the  hope  of  finding  more  favorable  sand 
conditions.  Further  testing  would  be  especially  desirable  if  encouraging 
showings  are  found  in  the  first  test. 


SORENTO    DOME  1L 

Assuming  that  an  oil  sand  exists  in  the  region  having  a  structure  similar 
to  that  shown  for  Herrin  (No.  6)  coal,  the  most  probable  location  of  oil 
pools  therein  is  in  the  upper  parts  of  the  New  Douglas  dome  and  the  Panama 
anticline.  On  account  of  the  lack  of  proof  for  any  reverse  dip  the  Panama 
anticline  does  not  seem  to  be  as  favorable  a  structure  for  oil  accumulation 
as  the  New  Douglas  dome,  but  at  the  same  time  it  should  be  noted  thait 
because  of  the  lack  of  drilling,  the  structure  in  the  area  to  the  west  of  the 
Panama  anticline  is  not  well  known.  If  production  is  secured  from  the  New 
Douglas  dome  it  would  be  desirable  to  test  the  Panama  anticline  as  well, 
making  a  location  not  far  from  its  summit  as  shown  in  figure  2  (sec.  28, 
T.  7  N.,  R.  4  W.). 

If,  however,  oil  sands  exist  in  the  region  in  those  lower  strata  which  are. 
separated  from  Herrin  (No.  6)  coal  by  one  or  more  important  unconformi- 
ties, the  relations  of  the  possible  oil  pools  to  the  structure  of  Herrin  (No.  6) 
coal  are  not  likely  to  be  so  simple.  This  was  found  to  be  true  for  the  Lange- 
wisch-Kuester  and  Brown  pools  east  of  Centralia  where  the  production, 
coming  from  a  sand  in  the  lower  part  of  the  Chester,  is  found  on  the  slopes 
of  the  anticlinal  structures  in  Herrin  (No.  6)  coal."  Hence,  the  possibilities 
of  production  in  a  region  cannot  be  said  to  be  exhausted  even  when  the 
upper  parts  of  the  anticlines  in  Herrin  (No.  6)  coal  have  been  tested. 

At  the  present  time  definite  recommendations  based  on  adequate  knowl- 
edge of  the  structure  of  pre-Pennsylvanian  strata  in  southwestern  Illinois 
in  general  and  in  the  Sorento  dome  area  in  particular  cannot  be  made.  In 
the  future,  as  knowledge  of  these  deeper  strata  gradually  accumulates,  and 
as  more  accurate  data  are  obtained  from  more  carefully  kept  logs,  the 
geological  guidance  of  oil  prospecting  will  be  of  greater  service  than  is  at 
present  possible. 

Conclusions 

The  New  Douglas  dome  is  a  structure  with  more  than  the  usual  amount 
of  closure,  situated  in  a  region  in  which  oil  and  gas  have  been  produced  from 
structures  having  less  closure.  The  upper  part  of  the  structure  has  not  yet 
been  tested  for  oil.  The  presence  of  a  number  of  sands  of  Pennsylvanian 
age  upon  the  dome  has  been  demonstrated,  and  it  is  probable  that  Missis- 
sippian  sands  are  also  present.  In  view  of  (1)  the  unusually  favorable 
structure,  and  (2)  the  presence  of  possible  reservoir  sands,  it  is  recom- 
mended that  one  or  more  test  wells  be  drilled  in  this  area. 


8  Bell,  A.  H.,  Oil  investigations  in  the  Centralia  area — preliminary  report:  Illinois 
State  Geol.  Survey  Press  Bulletin  Series,  Illinois  Petroleum  No.  4,  pp.  6-10,  August  28, 
1926. 


